Out with the old and in with the new. It’s a saying that describes the current state of perhaps the most revered cast in Ultimate Fighter history. The first season of TUF created a spark in the MMA world, particularly with the UFC, that we may never witness again.

It is defined by a single fight, Forrest Griffin vs. Stephan Bonnar. Now with both Griffin and Bonnar officially hanging up the gloves and preparing for an UFC Hall of Fame induction, there are only four left standing. Only four of the original participants are still competing in the UFC and they are Josh Koscheck, Mike Swick, Diego Sanchez and Chris Leben.

As the days go by and fighters from the initial boom period following TUF retire, don’t be surprised to see a few more of those men hanging up the gloves. But which of the remaining active fighters has the best chance to maintain their career?

Looking at Koscheck, you have a guy who came into the sport as a pure wrestler. He brought some of the best amateur wrestling credentials in MMA, but added some striking dimensions to his game. Koscheck enjoyed quite a run after appearing on TUF 1. He eventually challenged for the UFC title at UFC 124. In recent times, however, Koscheck has clearly slowed. He’s just 2-3 in his last five bouts, including a disastrous showing against Georges St-Pierre at UFC 124 that left him with a broken orbital bone. He was able to at least make it interesting against Johny Hendricks and could very easily complain about the stoppage loss to Robbie Lawler. He’s scheduled to face Demian Maia next, but regardless of how that fight turns out, it’s clear that Koscheck’s days as a title contender are behind him. He is focused on the “big money” fights, and that’s the right mindset for him to have at this stage in his career.

Koscheck’s nemesis on TUF 1 was Leben. The two were bitter rivals, and just as Koscheck rose to prominence by playing the bad guy, Leben saw his rise by becoming a fan favorite. Aside from his time on the show, Leben also became one of the UFC’s best middleweights by winning four straight inside the Octagon. However, after his destruction at the hands of Anderson Silva, “The Crippler” was never the same. He enjoyed a bit of a career resurgence in 2010, but his personal demons caught up to him. That’s part of the reason Leben won’t enjoy as much success in his final years of competing. Every time he seems to get a bit of momentum going, his personal demons always seem to catch up to him. Along with his issues outside the cage, Leben also has some to face inside it. His legendary granite chin has failed him on two occasions against Brian Stann and Mark Munoz. Along with his chin beginning to fade, Leben looked incredibly lethargic against Derek Brunson. With his best defensive weapon beginning to fail him and question marks in his personal life, don’t anticipate Leben pulling off another career resurgence.

Like Leben, Swick also enjoyed a pretty successful run during his UFC tenure. The American Kickboxing Acadmey fighter was once considered a top-five welterweight competitor and came within one fight from challenging GSP for the welterweight title. “Quick” Swick, as he came to be known, had a knack for lightning-fast punches and a slick ground game. Those seem to be a thing of the past now that Swick has gone just 1-3 in his past four fights. The losses to Dan Hardy and Matt Brown are particularly telling about where Swick ranks in the UFC’s welterweight division. Hardy rocked Swick multiple times in their contest and Brown became the only man besides Leben to knock out the AKA fighter. The losses, combined with his time away from action while contending with a stomach disease, have dropped Swick from title contention. However, Swick is still a dangerous opponent and despite being 33 years old, he has only fought 20 times. If Swick can prove that his chin can withstand some punishment, he can become one of the UFC’s better gatekeeper fighters.

The man who could enjoy perhaps the most success in his final years of action is Sanchez, one of the winners of TUF 1. If he can ever get the weight cutting thing down, Sanchez still has the ability to become a real threat in the lightweight division. After being picked apart and left a bloody mess by B.J. Penn and getting embarrassed by John Hathaway, Sanchez rebounded with one of his best outings against the always game Paulo Thiago. Sanchez followed that up with an amazing performance against Martin Kampmann, and although his face resembled hamburger meat, Sanchez gave it just as good as he took it. He did lose to Jake Ellenberger in his next outing, but then notched a win over Takanori Gomi. Although Sanchez’s performance against Gomi was less than thrilling, Sanchez’s track record makes it easy to believe that better things are ahead for the Greg Jackson-coached fighter.

What will make Sanchez the best pick among these four men to have more success going forward is that he seems to be the one with the most left in the gas tank. He continues to set an intense pace in each of his fights and doesn’t have to worry about having his lights turned off by his opponent. Sanchez also has his grappling base, which is still very good, to fall back on.

Although Sanchez will likely enjoy the most success out of the final four, it would be a shock to see any of these men near the top of their respective weight classes before 2013 closes. Koscheck and Leben are on two-fight losing skids, Swick is coming off a devastating knockout loss, and although Sanchez had his hand raised against Gomi, it was by the slimmest of margins. Look for the UFC to build cards on Fox Sports 1 with these fighters, since they still carry drawing power due to their big names (and mouth in the case of Koscheck). They will likely go down swinging and give the young crop of talent a tough fight, but it’s obvious the clock is ticking on what is widely regarded as the best season of The Ultimate Fighter.

Nothing beats the original, I suppose.

Photo: Diego Sanchez (Rob Tatum/The MMA Corner)